Safety device for aircraft seat ejectors



3 Sheets-Sheet l lNl/ENTOR ATTORNEYS I I L i Jan. 5, 1954 M. J. O. LOBELLE SAFETY DEVICE FOR AIRCRAFT SEAT EJECTORS Filed Feb. 14, 1952 J 5 M.- J. o. LOBELLE SAFETY DEVICE FOR AIRCRAFT SEAT EJECTORS 5 SheetsSheet 2 Filed Feb. 14, 1952 HHIIIH lNVENTOR MFCH M0455 Jana/y 105L115 J 1954 M. J. o. LOBELLE 2,665,088

SAFETY DEVICE FOR AIRCRAFT SEAT EJECTORS Filed Feb. 14, 1952 5 Sheets-Sheet S wad (/0155 3011M [055115 BY wwdwww ATTORNEKS Patented Jan. 5, 1 954 Ultimo erase-s ear orrice ZSAFETYIDEVIGE FOR AIRCRAFT SEAT EJE CTORS lVIarcelIliilesodilorrLbe1le,''Slough;"England, as-

signer "to M.

L. Aviation Companylimited,

"Claims*prloritnap lication GreatBritain February 19,1951

Claims. iiivei'itloh rel'ates to seateiectmn apparatos =ror-aireraft and-compri es a I modifi ation. of "the apparatus' described in'= Patent-No. -57 9;683. According to thePateht"No -2;579,683.;seat ei'e'cth seat is-adapted' to be ejected 'throug-h antipe'nin theaireraftpy the pressure-creases. enerased bv explosive charge-comprises eeleoncv1inders oper-atively interposed ectabie seat and' the aircraft, eiihau'st tube through wine-gases enerated "bythe expwsive'enarge pairbe "dissipated in case or inadvertent firing, and a movabre breech 'atlapted toholdtheexplosive charge, the mov aide inreech being normally in communication with the exhaust mice but inbvable int0 'c0m- 'fiiur'ricatioh' with the ej ecti'on 'cylihd'ers by proper operation or the ejection apparatus.

' The object f the present invention is "broadly the same in that is concerned withmehdering harmless the "consequences of "accidental "firing, but inparuoularthe ebjeet is to'p'rovide asa'fety neviceror m con-junction with a fixe'd' breech.

according to tne inven'tion, --a-:gm1 roe-seat ejectionhasa hreechforholding*theexplosivepharge arid-which 'i's relation-to at leasttwo telescopically-arrangedej ectrorr cylinders *andto -an exhaust tube, through =whibh-tl'ie gases generated 'by the-efiplosive charge'canbe dissipated in case of inadvertent firing, while a movable valve is arranged norma'nvtosearthe entry to the ejection cylinfiers iziutfis movable uponiproper operation of --:the ejection apparatus into a position where it-seals the entry to tl'ie exhaust tube.

Prferably the valve is a iiap valve having a pair of parallel faced discs which are together joined on thehall lieaded*arfnattached to a valve 'spmdle, thus giving a: small angular: move mentee as to ensure accurate seating in both of its alte native positions, The v lv is p reted by a cam m chanism whi h p i r to act tion, locks the v lve n i s safe position wh re it closes the entry to the ej ction cylin A s f ty evice for an e ect n un ac in to h invention is illu trate in h acc mpanying drawin s. which:

Figure 1 is a sec ion l Iroh view showin a valve chamber;

Figure 2. is a secti n l pl n view ak n on h line 11-11 of Figure 1;

Figure 3 is a front view showing a cam in the safe position;

Figure 4 is a front view showing the operation of the cam.

The cylinders of the gun are arranged so that :-'t1on ap aratus for aircraft of *the kind wherein the outer ejection cylinder attacheda its upper end a trunnion block 2 having '1ugs 3-tht project from each side into 'bearing-hlock's i'fl, thus forming a pivotal 'conn'ec'tionto f the s'eat back structure as in Patent 'No. 2,5'7-9;68'3. The cylinder 1 is thus :the exactcounterpart of the cylinder- 42- shown in thedraw-ings'o'f' the aromsaid patent.

The central portion of the block fl iiesapetween the outer ejection cylinder l, and a breec tube e screw-threaded "thereto thus-leaving a Waive chamber 5 within the-block 'The' valve cham her 5 has one'outl'et ficonnectedto the-ejection cylinder 1 anda furtheroutlet lileadin Lto an exhaust 1 tube 8 :which is retained ton ithe smock 2 by screws 35. .Th'e bre'ech tube-=4 is mounted with itsaxis parallel to, .but isslightly ofisetzfrom the axis of the ejection cylinder .1. Inathe valve chamioerfi is a flap valves} composed of twosflat parallel faced discs- I!) having a:space between them to allow a triangularishaped'i'ballzhea ded arm H to be held th-ere-in,vthus allowing :foraa small angular v movement which allows the valve to seat: properly over the.required-apertureiir the valve chamber. The ball headed -arm H is mounted on a spindle I2 which is mountedwithin the block 2, one end being contained in recess l3 of the block 2 and the other endlin bearing I l screwsthreaded in the b1ock 2 and retaining the valve spindle c L2 thereinfby acsplit ring l5 mounted in asgrooveifi in the spindle 12-. The spindle l2 is made of resilient material to act as a torsion spring whenholding the valve in either position. The split ring l5ris held/in position by means of a threaded retaining I! screwed into the bearing [4. Attachedto-the valve spindle I2 is a bell-crank lever [8 having astud [9 on one of its arms which engages-a slot 22 of a cam plate 20 pivoted at'2l on the block 2t The safe position of theg-un (shown Fig.3) is when the second arm 3! of the bell-crank; lever 18 is h ld between rais d su f ce 23 n 32 on the ear fa e f t e cam plate 0, t us keep ng the valve in a position which covers the aperture 6 le i g t the eje i n cylinders, In operati n t e cam pl t 20 s move y a rod 24 att ched to an x ension 25 o the am. p t 20, pivoted at 26. Wh n rod 24 s pu led in a. downward i e ti n, it ro ks the cam plat 20 in a cl ckwi e direction. The fir t e ect f his movement is that the stud [9 moves along a portion 22:; of the slot 22, and since this portion forms an arc of a circle about pivot 2|, no appreciable movement is transmitted to the stud I9. Further movement of the plate 20 forces the stud l9 around a right-angled bend no so that the stud l9 rides up the shoulder of the bend and thereby rocks the lever I8 into the horizontal position shown in Figure 4. This in turn moves the valve 9 to a position which covers the aperture 1 leading to the exhaust tube 8 (broken line position in Figure 1). Once the stud l9 has passed the bend 22b, it moves into a portion 21 of the slot 22, which is again a portion of a circle described about the pivot 2|, which thus imparts no further movement to the stud but looks it in position, thus firmly holding the valve 9 on its seating covering the exhaust tube 8. As shown'in Figure 4, the stud has just entered the portion 21 of the slot, the dotted line showing successive positions of the cam plate 20. The provision of the portion 21 of the slot 22 in addition to locking the stud allows the cam plate to turn further until it engages a roller 28 on a push rod 29, which is connected to the firing mechanism of the gun contained in the head of the breech 4 as indicated by arrow 30. When the firing mechanism is released the gas from the explosive charge passes into the ejection cylinder, since the valve 9 is covering the aperture 1 leading to the exhaust tube 8 and not the aperture 6 as when in the safe position. It will be appreciated that any type of valve such as a poppet valve may conveniently be used.

I claim:

1. In an aircraft, in combination with a seat, a gun for seat ejection comprising in combination breech means and firing means for firing an explosive charge enclosed within said breech means, said breech means being connected to said seat, an ejection cylinder, an exhaust tube through which gases can be dissipated in case of inadvertent firing of said explosive charge, said breech means being rigidly connected to and in communication with said ejection cylinder and said exhaust tube, valve means for sealing alternatively said ejection cylinder or said exhaust tube from said breech means, means for moving said valve means from sealing relationship with said ejection cylinder to sealing relationship with said exhaust tube, and means for operating said firing means in timed relation with said valve means.

2. A gun'as claimed in claim 1 in which said valve means is a flap valve comprising a valve spindle, a ball headed arm attached to said valve spindle,.a pair of parallel faced discs joined together on said ball headed arm, said ball headed arm givinga small angular movement so as to ensure accurate sealing relationship with said valve in both of its alternative positions.

3. A gun as claimed in claim 2 comprising a bell-crank lever attached to said valve spindle, a stud attached to one arm of said bell crank lever, a cam plate with a slot so formed to engage said stud of said bell-crank lever and a pivot supporting said cam plate on said breech means. 4. A gun as claimed in claim 3 in which the contour of said slot of said cam plate comprises two portions, the first for turning said valve from its sealing relationship with said ejection cylinders by means of said stud on said bell-crank lever and the second, on further rotation of said cam plate for holding said stud in a position which locks said valve into sealing relationship with said exhaust tube.

5. In an aircraft, in combination with a seat, a gun for seat ejection comprising in combination, breech means and firing means for firing an explosive charge enclosed within said breech means, a hollow trunnion block connected to said seat, said breech means being connected to said hollow trunnion block, an ejection cylinder, an exhaust tube through which gases can be dissipated in case of inadvertent firing of said explosive charge, said ejection cylinder and said exhaust tube being connected to and in communication with said hollow trunnion block, a flap valve, a ball-headed arm attached to said flap valve, said ball-headed arm giving a small angular movement so as to ensure accurate sealing relationship with said valve in both of its alternative positions, a spindle mounted within said hollow trunnion block and attached to said ball-headed arm of said flap valve, a bell-crank lever having two arms and attached to said spindle, a stud on one of said arms of said bell-crank lever, a cam plate with a slot so formed to engage said stud on said bell-crank lever, the rear of said cam plate being formed with a pair of raised portions, said raised portions cooperating to engage the second arm of said bell-cranklever References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,559,183 Rimailho Oct. 27, 1925 2,541,087 Musser Feb. 13, 1951 FOREIGN PATENTS Number Country Date 747,296 France Mar. 28, 1933 

